Fastener Coating Pattern for Lubricity and Electrical Dispersion
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Solution Overview
Problem
Fasteners used in the aerospace industry face challenges in balancing structural strength and electrical conductivity, as coatings that enhance lubricity for easier installation can electrically insulate the fasteners, while metal sleeves for energy dissipation are costly and inefficient.
Innovation Solution
Applying an irregular, non-uniform metal pigmentation or dry film lubricant coating to fasteners, which leaves exposed regions for electrical conductivity and covered regions for increased lubricity, allowing for efficient energy dissipation without compromising structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a coating is applied to enhance lubricity, then the installation force is reduced, but the electrical conductivity is compromised
Solution Approach 1:
The fastener surface is coated with lubricant in specific localized regions rather than uniformly across the entire surface. The coating is applied to areas that contact the hole during installation to reduce friction, while leaving exposed metal regions that provide electrical conductivity pathways. This local differentiation resolves the contradiction by applying lubricity enhancement only where mechanically needed while preserving electrical conductivity where required.
Solution Approach 2:
The fastener surface is segmented into distinct coated and uncoated regions. The coating process creates discrete lubricated zones separated by exposed metal areas, allowing the fastener to simultaneously exhibit both low friction (in coated regions) and good electrical conductivity (in uncoated regions). This segmentation enables the fastener to fulfill both lubricity and conductivity requirements.
2Reliability
If a protective metal sleeve is used to provide energy dissipation, then the electrical energy dispersion is improved, but the cost increases
Solution Approach 1:
The patent extracts the essential function of the metal sleeve (electrical energy dissipation) and implements it directly through the fastener's own metal surface regions. By leaving portions of the fastener surface uncoated, the inherent electrical conductivity of the metal fastener is utilized for energy dissipation, eliminating the need for an additional expensive metal sleeve component while maintaining the energy dissipation function.
Solution Approach 2:
The patent uses the fastener's own metal surface as a disposable/consumable element for electrical energy dissipation. The exposed metal regions on the fastener surface serve as sacrificial conductive paths that can dissipate electrical energy during service, replacing the need for expensive protective metal sleeves while achieving the same functional outcome.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces installation force and prevents electrical arcing while maintaining structural integrity and cost-effectiveness, as the coating enhances lubricity without compromising electrical conductivity, and can be adjusted for specific design requirements.
Implementation Method 1
application of the coating enhances lubricity without substantially compromising electrical conductivity of the fastener
Implementation Method 2
remaining exposed regions not covered by the coating provide desired levels of electrical energy dispersion at the fastener surface
Data Source
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AI summary
Systems and methods are provided for fabricating fasteners. One embodiment is an apparatus that includes a fastener (250). The fastener includes a head (430), a cylindrical shank (440) that extends from the head and is dimensioned to engage in a fit with a corresponding hole, and a coating (510) that is discontinuously speckled around a circumference of the shank and extends axially along the shank, leaving irregular portions of a surface of the shank exposed. The coating exhibits a higher lubricity than the surface, and the coating exhibits a higher dielectric withstand voltage than the surface.